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<h1>HUnit 1.0 User's Guide</h1>

HUnit is a unit testing framework for Haskell, inspired by the JUnit
tool for Java.&nbsp; This guide describes how to use HUnit, assuming
you are familiar with Haskell, though not necessarily with
JUnit.&nbsp; You can obtain HUnit, including this guide, at
<a href="http://hunit.sourceforge.net">http://hunit.sourceforge.net</a>.

<h2>Introduction</h2>

A test-centered methodology for software development is most effective
when tests are easy to create, change, and execute.&nbsp; The <a
href="http://www.junit.org">JUnit</a> tool pioneered support for
test-first development in <a href="http://java.sun.com">Java</a>.&nbsp;
HUnit is an adaptation of JUnit to Haskell, a general-purpose, purely
functional programming language.&nbsp; (To learn more about Haskell,
see <a href="http://www.haskell.org">http://www.haskell.org</a>.)
<p>
With HUnit, as with JUnit, you can easily create tests, name them,
group them into suites, and execute them, with the framework checking
the results automatically.&nbsp; Test specification in HUnit is even
more concise and flexible than in JUnit, thanks to the nature of the
Haskell language.&nbsp; HUnit currently includes only a text-based
test controller, but the framework is designed for easy
extension.&nbsp; (Would anyone care to write a graphical test
controller for HUnit?)
<p>
The next section helps you get started using HUnit in simple
ways.&nbsp; Subsequent sections give details on <a
href="#WritingTests">writing tests</a> and <a
href="#RunningTests">running tests</a>.&nbsp; The document concludes
with a section describing HUnit's <a
href="#ConstituentFiles">constituent files</a> and a section giving
<a href="#References">references</a> to further information.

<h2><a name="GettingStarted">Getting Started</a></h2>

In the Haskell module where your tests will reside, import module
<tt>HUnit</tt>:
<pre>
    import HUnit
</pre>
Define test cases as appropriate:
<pre>
    test1 = TestCase (assertEqual "for (foo 3)," (1,2) (foo 3))
    test2 = TestCase (do (x,y) &lt;- partA 3
                         assertEqual "for the first result of partA," 5 x
                         b &lt;- partB y
                         assertBool ("(partB " ++ show y ++ ") failed") b)
</pre>
Name the test cases and group them together:
<pre>
    tests = TestList [TestLabel "test1" test1, TestLabel "test2" test2]
</pre>
Run the tests as a group.&nbsp; At a Haskell interpreter prompt, apply
the function <tt>runTestTT</tt> to the collected tests.&nbsp; (The
"<tt>TT</tt>" suggests <b><u>t</u></b>ext orientation with output to
the <b><u>t</u></b>erminal.)
<pre>
    > runTestTT tests
    Cases: 2  Tried: 2  Errors: 0  Failures: 0
    >
</pre>
If the tests are proving their worth, you might see:
<pre>
    > runTestTT tests
    ### Failure in: 0:test1
    for (foo 3),
    expected: (1,2)
     but got: (1,3)
    Cases: 2  Tried: 2  Errors: 0  Failures: 1
    >
</pre>
Isn't that easy?
<p>
You can specify tests even more succinctly using operators and
overloaded functions that HUnit provides:
<pre>
    tests = test [ "test1" ~: "(foo 3)" ~: (1,2) ~=? (foo 3),
                   "test2" ~: do (x, y) &lt;- partA 3
                                 assertEqual "for the first result of partA," 5 x
                                 partB y @? "(partB " ++ show y ++ ") failed" ]
</pre>
Assuming the same test failures as before, you would see:
<pre>
    > runTestTT tests
    ### Failure in: 0:test1:(foo 3)
    expected: (1,2)
     but got: (1,3)
    Cases: 2  Tried: 2  Errors: 0  Failures: 1
    >
</pre>

<h2><a name="WritingTests"></a>Writing Tests</h2>

Tests are specified compositionally.&nbsp; <a
href="#Assertions">Assertions</a> are combined to make a <a
href="#TestCase">test case</a>, and test cases are combined into <a
href="#Tests">tests</a>.&nbsp; HUnit also provides <a
href="#AdvancedFeatures">advanced features</a> for more convenient
test specification.

<h3><a name="Assertions"></a>Assertions</h3>

The basic building block of a test is an <b>assertion</b>.
<pre>
    type Assertion = IO ()
</pre>
An assertion is an <tt>IO</tt> computation that always produces a void
result.&nbsp; Why is an assertion an <tt>IO</tt> computation?  So that
programs with real-world side effects can be tested.&nbsp; How does an
assertion assert anything if it produces no useful result?  The answer
is that an assertion can signal failure by calling
<tt>assertFailure</tt>.
<pre>
    assertFailure :: String -> Assertion
    assertFailure msg = ioError (userError ("HUnit:" ++ msg))
</pre>
<tt>(assertFailure msg)</tt> raises an exception.&nbsp; The string
argument identifies the failure.&nbsp; The failure message is prefixed
by "<tt>HUnit:</tt>" to mark it as an HUnit assertion failure
message.&nbsp; The HUnit test framework interprets such an exception
as indicating failure of the test whose execution raised the
exception.&nbsp; (Note: The details concerning the implementation of
<tt>assertFailure</tt> are subject to change and should not be relied
upon.)
<p>
<tt>assertFailure</tt> can be used directly, but it is much more
common to use it indirectly through other assertion functions that
conditionally assert failure.
<pre>
    assertBool :: String -> Bool -> Assertion
    assertBool msg b = unless b (assertFailure msg)

    assertString :: String -> Assertion
    assertString s = unless (null s) (assertFailure s)

    assertEqual :: (Eq a, Show a) => String -> a -> a -> Assertion
    assertEqual preface expected actual =
      unless (actual == expected) (assertFailure msg)
     where msg = (if null preface then "" else preface ++ "\n") ++
                 "expected: " ++ show expected ++ "\n but got: " ++ show actual
</pre>
With <tt>assertBool</tt> you give the assertion condition and failure
message separately.&nbsp; With <tt>assertString</tt> the two are
combined.&nbsp; With <tt>assertEqual</tt> you provide a "preface", an
expected value, and an actual value; the failure message shows the two
unequal values and is prefixed by the preface.&nbsp; Additional ways
to create assertions are described later under <a
href="#AdvancedFeatures">Advanced Features</a>.
<p>
Since assertions are <tt>IO</tt> computations, they may be
combined--along with other <tt>IO</tt> computations--using
<tt>(>>=)</tt>, <tt>(>>)</tt>, and the <tt>do</tt> notation.&nbsp; As
long as its result is of type <tt>(IO ())</tt>, such a combination
constitutes a single, collective assertion, incorporating any number
of constituent assertions.&nbsp; The important features of such a
collective assertion are that it fails if any of its constituent
assertions is executed and fails, and that the first constituent
assertion to fail terminates execution of the collective
assertion.&nbsp; Such behavior is essential to specifying a test case.

<h3><a name="TestCase"></a>Test Case</h3>

A <b>test case</b> is the unit of test execution.&nbsp; That is,
distinct test cases are executed independently.&nbsp; The failure of
one is independent of the failure of any other.
<p>
A test case consists of a single, possibly collective,
assertion.&nbsp; The possibly multiple constituent assertions in a
test case's collective assertion are <b>not</b> independent.&nbsp;
Their interdependence may be crucial to specifying correct operation
for a test.&nbsp; A test case may involve a series of steps, each
concluding in an assertion, where each step must succeed in order for
the test case to continue.&nbsp; As another example, a test may
require some "set up" to be performed that must be undone ("torn down"
in JUnit parlance) once the test is complete.&nbsp; In this case, you
could use Haskell's <tt>IO.bracket</tt> function to achieve the
desired effect.
<p>
You can make a test case from an assertion by applying the
<tt>TestCase</tt> constructor.&nbsp; For example,
<tt>(TestCase&nbsp;(return&nbsp;()))</tt> is a test case that never
fails, and
<tt>(TestCase&nbsp;(assertEqual&nbsp;"for&nbsp;x,"&nbsp;3&nbsp;x))</tt>
is a test case that checks that the value of <tt>x</tt> is 3.&nbsp;
Additional ways to create test cases are described later under
<a href="#AdvancedFeatures">Advanced Features</a>.

<h3><a name="Tests"></a>Tests</h3>

As soon as you have more than one test, you'll want to name them to
tell them apart.&nbsp; As soon as you have more than several tests,
you'll want to group them to process them more easily.&nbsp; So,
naming and grouping are the two keys to managing collections of tests.
<p>
In tune with the "composite" design pattern [<a
href="#DesignPatterns">1</a>], a <b>test</b> is defined as a package
of test cases.&nbsp; Concretely, a test is either a single test case,
a group of tests, or either of the first two identified by a label.
<pre>
    data Test = TestCase Assertion
              | TestList [Test]
              | TestLabel String Test
</pre>
There are three important features of this definition to note:
<ul>
<li>
A <tt>TestList</tt> consists of a list of tests rather than a list of
test cases.&nbsp; This means that the structure of a <tt>Test</tt> is
actually a tree.&nbsp; Using a hierarchy helps organize tests just as
it helps organize files in a file system.
</li>
<li>
A <tt>TestLabel</tt> is attached to a test rather than to a test
case.&nbsp; This means that all nodes in the test tree, not just test
case (leaf) nodes, can be labeled.&nbsp; Hierarchical naming helps
organize tests just as it helps organize files in a file system.
</li>
<li>
A <tt>TestLabel</tt> is separate from both <tt>TestCase</tt> and
<tt>TestList</tt>.&nbsp; This means that labeling is optional
everywhere in the tree.&nbsp; Why is this a good thing?  Because of
the hierarchical structure of a test, each constituent test case is
uniquely identified by its path in the tree, ignoring all
labels.&nbsp; Sometimes a test case's path (or perhaps its subpath
below a certain node) is a perfectly adequate "name" for the test case
(perhaps relative to a certain node).&nbsp; In this case, creating a
label for the test case is both unnecessary and inconvenient.
</li>
</ul>
<p>
The number of test cases that a test comprises can be computed with
<tt>testCaseCount</tt>.
<pre>
    testCaseCount :: Test -> Int
</pre>
<p>
As mentioned above, a test is identified by its <b>path</b> in the
test hierarchy.
<pre>
    data Node  = ListItem Int | Label String
      deriving (Eq, Show, Read)

    type Path = [Node]    -- Node order is from test case to root.
</pre>
Each occurrence of <tt>TestList</tt> gives rise to a <tt>ListItem</tt>
and each occurrence of <tt>TestLabel</tt> gives rise to a
<tt>Label</tt>.&nbsp; The <tt>ListItem</tt>s by themselves ensure
uniqueness among test case paths, while the <tt>Label</tt>s allow you
to add mnemonic names for individual test cases and collections of
them.
<p>
Note that the order of nodes in a path is reversed from what you might
expect: The first node in the list is the one deepest in the
tree.&nbsp; This order is a concession to efficiency: It allows common
path prefixes to be shared.
<p>
The paths of the test cases that a test comprises can be computed with
<tt>testCasePaths</tt>.&nbsp; The paths are listed in the order in
which the corresponding test cases would be executed.
<pre>
    testCasePaths :: Test -> [Path]
</pre>
<p>
The three variants of <tt>Test</tt> can be constructed simply by
applying <tt>TestCase</tt>, <tt>TestList</tt>, and <tt>TestLabel</tt>
to appropriate arguments.&nbsp; Additional ways to create tests are
described later under <a href="#AdvancedFeatures">Advanced
Features</a>.
<p>
The design of the type <tt>Test</tt> provides great conciseness,
flexibility, and convenience in specifying tests.&nbsp; Moreover, the
nature of Haskell significantly augments these qualities:
<ul>
<li>
Combining assertions and other code to construct test cases is easy
with the <tt>IO</tt> monad.
</li>
<li>
Using overloaded functions and special operators (see below),
specification of assertions and tests is extremely compact.
</li>
<li>
Structuring a test tree by value, rather than by name as in JUnit,
provides for more convenient, flexible, and robust test suite
specification.&nbsp; In particular, a test suite can more easily be
computed "on the fly" than in other test frameworks.
</li>
<li>
Haskell's powerful abstraction facilities provide unmatched support
for test refactoring.
</li>
</ul>

<h3><a name="AdvancedFeatures"></a>Advanced Features</h3>

HUnit provides additional features for specifying assertions and tests
more conveniently and concisely.&nbsp; These facilities make use of
Haskell type classes.
<p>
The following operators can be used to construct assertions.
<pre>
    infix 1 @?, @=?, @?=

    (@?) :: (AssertionPredicable t) => t -> String -> Assertion
    pred @? msg = assertionPredicate pred >>= assertBool msg

    (@=?) :: (Eq a, Show a) => a -> a -> Assertion
    expected @=? actual = assertEqual "" expected actual

    (@?=) :: (Eq a, Show a) => a -> a -> Assertion
    actual @?= expected = assertEqual "" expected actual
</pre>
You provide a boolean condition and failure message separately to
<tt>(@?)</tt>, as for <tt>assertBool</tt>, but in a different
order.&nbsp; The <tt>(@=?)</tt> and <tt>(@?=)</tt> operators provide
shorthands for <tt>assertEqual</tt> when no preface is required.&nbsp;
They differ only in the order in which the expected and actual values
are provided.&nbsp; (The actual value--the uncertain one--goes on the
"?" side of the operator.)
<p>
The <tt>(@?)</tt> operator's first argument is something from which an
assertion predicate can be made, that is, its type must be
<tt>AssertionPredicable</tt>.
<pre>
    type AssertionPredicate = IO Bool

    class AssertionPredicable t
     where assertionPredicate :: t -> AssertionPredicate

    instance AssertionPredicable Bool
     where assertionPredicate = return

    instance (AssertionPredicable t) => AssertionPredicable (IO t)
     where assertionPredicate = (>>= assertionPredicate)
</pre>
The overloaded <tt>assert</tt> function in the <tt>Assertable</tt>
type class constructs an assertion.
<pre>
    class Assertable t
     where assert :: t -> Assertion

    instance Assertable ()
     where assert = return

    instance Assertable Bool
     where assert = assertBool ""

    instance (ListAssertable t) => Assertable [t]
     where assert = listAssert

    instance (Assertable t) => Assertable (IO t)
     where assert = (>>= assert)
</pre>
The <tt>ListAssertable</tt> class allows <tt>assert</tt> to be applied
to <tt>[Char]</tt> (that is, <tt>String</tt>).
<pre>
    class ListAssertable t
     where listAssert :: [t] -> Assertion

    instance ListAssertable Char
     where listAssert = assertString
</pre>
With the above declarations, <tt>(assert&nbsp;())</tt>,
<tt>(assert&nbsp;True)</tt>, and <tt>(assert&nbsp;"")</tt> (as well as
<tt>IO</tt> forms of these values, such as <tt>(return&nbsp;())</tt>)
are all assertions that never fail, while <tt>(assert&nbsp;False)</tt>
and <tt>(assert&nbsp;"some&nbsp;failure&nbsp;message")</tt> (and their
<tt>IO</tt> forms) are assertions that always fail.&nbsp; You may
define additional instances for the type classes <tt>Assertable</tt>,
<tt>ListAssertable</tt>, and <tt>AssertionPredicable</tt> if that
should be useful in your application.
<p>
The overloaded <tt>test</tt> function in the <tt>Testable</tt> type
class constructs a test.
<pre>
    class Testable t
     where test :: t -> Test

    instance Testable Test
     where test = id

    instance (Assertable t) => Testable (IO t)
     where test = TestCase . assert

    instance (Testable t) => Testable [t]
     where test = TestList . map test
</pre>
The <tt>test</tt> function makes a test from either an
<tt>Assertion</tt> (using <tt>TestCase</tt>), a list of
<tt>Testable</tt> items (using <tt>TestList</tt>), or a <tt>Test</tt>
(making no change).
<p>
The following operators can be used to construct tests.
<pre>
    infix  1 ~?, ~=?, ~?=
    infixr 0 ~:

    (~?) :: (AssertionPredicable t) => t -> String -> Test
    pred ~? msg = TestCase (pred @? msg)

    (~=?) :: (Eq a, Show a) => a -> a -> Test
    expected ~=? actual = TestCase (expected @=? actual)

    (~?=) :: (Eq a, Show a) => a -> a -> Test
    actual ~?= expected = TestCase (actual @?= expected)

    (~:) :: (Testable t) => String -> t -> Test
    label ~: t = TestLabel label (test t)
</pre>
<tt>(~?)</tt>, <tt>(~=?)</tt>, and <tt>(~?=)</tt> each make an
assertion, as for <tt>(@?)</tt>, <tt>(@=?)</tt>, and <tt>(@?=)</tt>,
respectively, and then a test case from that assertion.&nbsp;
<tt>(~:)</tt> attaches a label to something that is
<tt>Testable</tt>.&nbsp; You may define additional instances for the
type class <tt>Testable</tt> should that be useful.

<h2><a name="RunningTests"></a>Running Tests</h2>

HUnit is structured to support multiple test controllers.&nbsp; The
first subsection below describes the <a href="#TestExecution">test
execution</a> characteristics common to all test controllers.&nbsp;
The second subsection describes the
<a href="#Text-BasedController">text-based controller</a> that is
included with HUnit.

<h3><a name="TestExecution">Test Execution</a></h3>

All test controllers share a common test execution model.&nbsp; They
differ only in how the results of test execution are shown.
<p>
The execution of a test (a value of type <tt>Test</tt>) involves the
serial execution (in the <tt>IO</tt> monad) of its constituent test
cases.&nbsp; The test cases are executed in a depth-first,
left-to-right order.&nbsp; During test execution, four counts of test
cases are maintained:
<pre>
    data Counts = Counts { cases, tried, errors, failures :: Int }
      deriving (Eq, Show, Read)
</pre>
<ul>
<li>
<tt>cases</tt> is the number of test cases included in the test.&nbsp;
This number is a static property of a test and remains unchanged
during test execution.
</li>
<li>
<tt>tried</tt> is the number of test cases that have been executed so
far during the test execution.
</li>
<li>
<tt>errors</tt> is the number of test cases whose execution ended with
an unexpected exception being raised.&nbsp; Errors indicate problems
with test cases, as opposed to the code under test.
</li>
<li>
<tt>failures</tt> is the number of test cases whose execution asserted
failure.&nbsp; Failures indicate problems with the code under test.
</li>
</ul>
Why is there no count for test case successes?  The technical reason
is that the counts are maintained such that the number of test case
successes is always equal to
<tt>(tried&nbsp;-&nbsp;(errors&nbsp;+&nbsp;failures))</tt>.&nbsp; The
psychosocial reason is that, with test-centered development and the
expectation that test failures will be few and short-lived, attention
should be focused on the failures rather than the successes.
<p>
As test execution proceeds, three kinds of reporting event are
communicated to the test controller.&nbsp; (What the controller does
in response to the reporting events depends on the controller.)
<ul>
<li>
<i>start</i> --
Just prior to initiation of a test case, the path of the test case and
the current counts (excluding the current test case) are reported.
</li>
<li>
<i>error</i> --
When a test case terminates with an error, the error message is
reported, along with the test case path and current counts (including
the current test case).
</li>
<li>
<i>failure</i> --
When a test case terminates with a failure, the failure message is
reported, along with the test case path and current counts (including
the current test case).
</li>
</ul>
Typically, a test controller shows <i>error</i> and <i>failure</i>
reports immediately but uses the <i>start</i> report merely to update
an indication of overall test execution progress.

<h3><a name="Text-BasedController">Text-Based Controller</a></h3>

A text-based test controller is included with HUnit.
<pre>
    runTestText :: PutText st -> Test -> IO (Counts, st)
</pre>
<tt>runTestText</tt> is generalized on a <i>reporting scheme</i> given
as its first argument.&nbsp; During execution of the test given as its
second argument, the controller creates a string for each reporting
event and processes it according to the reporting scheme.&nbsp; When
test execution is complete, the controller returns the final counts
along with the final state for the reporting scheme.
<p>
The strings for the three kinds of reporting event are as follows.
<ul>
<li>
A <i>start</i> report is the result of the function
<tt>showCounts</tt> applied to the counts current immediately prior to
initiation of the test case being started.
</li>
<li>
An <i>error</i> report is of the form
"<tt>Error&nbsp;in:&nbsp;&nbsp;&nbsp;<i>path</i>\n<i>message</i></tt>",
where <i>path</i> is the path of the test case in error, as shown by
<tt>showPath</tt>, and <i>message</i> is a message describing the
error.&nbsp; If the path is empty, the report has the form
"<tt>Error:\n<i>message</i></tt>".
</li>
<li>
A <i>failure</i> report is of the form
"<tt>Failure&nbsp;in:&nbsp;<i>path</i>\n<i>message</i></tt>", where
<i>path</i> is the path of the test case in error, as shown by
<tt>showPath</tt>, and <i>message</i> is the failure message.&nbsp; If
the path is empty, the report has the form
"<tt>Failure:\n<i>message</i></tt>".
</li>
</ul>
<p>
The function <tt>showCounts</tt> shows a set of counts.
<pre>
    showCounts :: Counts -> String
</pre>
The form of its result is
"<tt>Cases:&nbsp;<i>cases</i>&nbsp;&nbsp;Tried:&nbsp;<i>tried</i>&nbsp;&nbsp;Errors:&nbsp;<i>errors</i>&nbsp;&nbsp;Failures:&nbsp;<i>failures</i></tt>"
where <i>cases</i>, <i>tried</i>, <i>errors</i>, and <i>failures</i>
are the count values.
<p>
The function <tt>showPath</tt> shows a test case path.
<pre>
    showPath :: Path -> String
</pre>
The nodes in the path are reversed (so that the path reads from the
root down to the test case), and the representations for the nodes are
joined by '<tt>:</tt>' separators.&nbsp; The representation for
<tt>(ListItem <i>n</i>)</tt> is <tt>(show n)</tt>.&nbsp; The
representation for <tt>(Label <i>label</i>)</tt> is normally
<i>label</i>.&nbsp; However, if <i>label</i> contains a colon or if
<tt>(show <i>label</i>)</tt> is different from <i>label</i> surrounded
by quotation marks--that is, if any ambiguity could exist--then
<tt>(Label <i>label</i>)</tt> is represented as <tt>(show
<i>label</i>)</tt>.
<p>
HUnit includes two reporting schemes for the text-based test
controller.&nbsp; You may define others if you wish.
<pre>
    putTextToHandle :: Handle -> Bool -> PutText Int
</pre>
<tt>putTextToHandle</tt> writes error and failure reports, plus a
report of the final counts, to the given handle.&nbsp; Each of these
reports is terminated by a newline.&nbsp; In addition, if the given
flag is <tt>True</tt>, it writes start reports to the handle as
well.&nbsp; A start report, however, is not terminated by a
newline.&nbsp; Before the next report is written, the start report is
"erased" with an appropriate sequence of carriage return and space
characters.&nbsp; Such overwriting realizes its intended effect on
terminal devices.
<pre>
    putTextToShowS :: PutText ShowS
</pre>
<tt>putTextToShowS</tt> ignores start reports and simply accumulates
error and failure reports, terminating them with newlines.&nbsp; The
accumulated reports are returned (as the second element of the pair
returned by <tt>runTestText</tt>) as a <tt>ShowS</tt> function (that
is, one with type <tt>(String&nbsp;->&nbsp;String)</tt>) whose first
argument is a string to be appended to the accumulated report lines.
<p>
HUnit provides a shorthand for the most common use of the text-based
test controller.
<pre>
    runTestTT :: Test -> IO Counts
</pre>
<tt>runTestTT</tt> invokes <tt>runTestText</tt>, specifying
<tt>(putTextToHandle stderr True)</tt> for the reporting scheme, and
returns the final counts from the test execution.

<h2><a name="ConstituentFiles">Constituent Files</a></h2>

HUnit 1.0 consists of the following files.
<dl>

<dt> Guide.html
<dd>
This document.
<dt> Example.hs
<dd>
Haskell module that includes the examples given in the <a
href="#GettingStarted">Getting Started</a> section.&nbsp; Run this
program to make sure you understand how to use HUnit.
<dt> HUnit.lhs
<dd>
Haskell module that you import to use HUnit.
<dt> HUnitBase.lhs
<dd>
Haskell module that defines HUnit's basic facilities.
<dt> HUnitLang.lhs
<dd>
Haskell module that defines how assertion failure is signaled and
caught.&nbsp; By default, it is a copy of
<tt>HUnitLang98.lhs</tt>.&nbsp; Replace it by a copy of
<tt>HUnitLangExc.lhs</tt> for more robust exception behavior.
<dt> HUnitLang98.lhs
<dd>
Haskell module that defines generic assertion failure handling.&nbsp;
It is compliant to Haskell 98 but catches only <tt>IO</tt> errors.
<dt> HUnitLangExc.lhs
<dd>
Haskell module that defines more robust assertion failure
handling.&nbsp; It catches more (though unfortunately not all) kinds
of exceptions.&nbsp; However, it works only with Hugs (Dec. 2001 or
later) and GHC (5.00 and later).
<dt> HUnitTest98.lhs
<dd>
Haskell module that tests HUnit, assuming the generic assertion
failure handling of <tt>HUnitLang98.lhs</tt>.
<dt> HUnitTestBase.lhs
<dd>
Haskell module that defines testing support and basic (Haskell 98
compliant) tests of HUnit (using HUnit, of course!).&nbsp; Contains
more extensive and advanced examples of testing with HUnit.
<dt> HUnitTestExc.lhs
<dd>
Haskell module that tests HUnit, assuming the extended assertion
failure handling of <tt>HUnitLangExc.lhs</tt>.
<dt> HUnitText.lhs
<dd>
Haskell module that defines HUnit's text-based test controller.
<dt> License
<dd>
The license for use of HUnit.
<dt> Terminal.lhs
<dd>
Haskell module that assists in checking the output of HUnit tests
performed by the text-based test controller.
<dt> TerminalTest.lhs
<dd>
Haskell module that tests <tt>Terminal.lhs</tt> (using HUnit, of
course!).
</dl>

<h2><a name="References">References</a></h2>

<dl>

<dt>
<a name="DesignPatterns"></a>[1] Gamma, E., et al. Design Patterns:
Elements of Reusable Object-Oriented Software, Addison-Wesley,
Reading, MA, 1995.
<dd>
The classic book describing design patterns in an object-oriented
context.

<dt>
<a href="http://www.junit.org">http://www.junit.org</a>
<dd>
Web page for JUnit, the tool after which HUnit is modeled.

<dt>
<a href="http://junit.sourceforge.net/doc/testinfected/testing.htm">
http://junit.sourceforge.net/doc/testinfected/testing.htm</a>
<dd>
A good introduction to test-first development and the use of JUnit.

<dt>
<a href="http://junit.sourceforge.net/doc/cookstour/cookstour.htm">
http://junit.sourceforge.net/doc/cookstour/cookstour.htm</a>
<dd>
A description of the internal structure of JUnit.&nbsp; Makes for an
interesting comparison between JUnit and HUnit.

</dl>

<p>
<hr>

The HUnit software and this guide were written by Dean Herington
(<a href="mailto:heringto@cs.unc.edu">heringto@cs.unc.edu</a>).

<p>
HUnit development is supported by
<a href="http://sourceforge.net">
<img src="http://sourceforge.net/sflogo.php?group_id=46796&type=1"
     width="88" height="31" border="0" alt="SourceForge.net Logo">
</a>

<p>
[$Revision: 1.1 $ $Date: 2004/03/01 19:46:30 $]

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